<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .progress {
          height: 25px;
          width: 400px;
          border-radius: 15px;
          background-color: #272425;
          border: 3px solid #272425;
          box-sizing: border-box;
          margin-bottom: 30px;
        }
        .inner {
          width: 50%;
          height: 20px;
          border-radius: 10px;
          text-align: right;
          position: relative;
          background-color: #409eff;
          background-size: 20px 20px;
          box-sizing: border-box;
          transition: all 1s;
        }
        .inner span {
          position: absolute;
          right: -20px;
          bottom: -25px;
        }
      </style>
</head>
<body>
    <div id="app">
      <!-- 外层盒子底色 （黑色） -->
      <div class="progress">
        <!-- 内层盒子 - 进度（蓝色） -->
        <div class="inner" :style="{width:percent + '%'}" >
          <span>{{percent}}%</span>
        </div>
      </div>
      <button @click="percent = 25">设置25%</button>
      <button @click="percent = 50">设置50%</button>
      <button @click="percent = 75">设置75%</button>
      <button @click="percent = 100">设置100%</button>
    </div>
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
    <script>
      const app = new Vue({
        el: '#app',
        data: {
          percent: 0
        }
      })
    </script>
  </body>
</html>